At 14:08 27/08/99 +1000, you wrote:
>>                 One rain measuring method we studied in a Physical
Geography
>>         class I took once is called the tipping bucket gauge.
>
>We've got a couple of these here even simpler.
>
>Just a small piece of tin pipe (100mm) cut in half (length wise). In the
>center, is a piece of metal that divides the two halves. This all pivots
>about it's center point on a pin. A small metal extension extends up
>from the bucket pivot point where a small magnet is attached. Each time
>one side of the bucket assembly fills it over balances, falls towards
>the heavy end and empties that side. The process continues with the
>opposite side filling. As the bucket assembly oscillates, the magnet
>passes a nearby reed switch momentarily closing the contacts.
>
>
>I had this idea simmering at the back of my head for a while now, and
>was wondering if a piezo sensor could be used to detect rain drops
>hitting it, or a surface attached to it. I thought it may make a rain
>detector for an automatic windscreen wiper.
>

Just what you need your wipers to come on when you are in the car wash :)
Pegot have tried this with sensors in the windscreen, seems that they would
also need to add a dirt detector to wash the screen at the start of a cycle
and losta uder tings that they hd fuggottun


Dennis



>--
>Best regards
>
>Tony
>
>http://www.picnpoke.com
>Email sales@picnpoke.com
>
>